IS 



a LOSS A nr of 



Division. 



SiMPi.K : \\\wM the blade is in one piece, however deeply it 

 may be rut. 



CoMPOUNii: when the blade is in two or more distinct pieces, 

 whi'li are then known as Iraflvts. 



A cijinix)und leaf is 



(a) Pinnate : when the leaflets are arranj^ed on each 

 side of a central or mid rib ; and such a pinnate leaf will 

 be (xld-pinnate if there is an odd leaflet at the end (Fig. 

 33) ; ahruptl If -pinnate if there is not a terminal leaflet 

 (Fig. 34) ; and pinnate with a ti-ndril if the mid-rib ends 

 in a tendril, as in Pea, etc. (Fig. 35). 



Again : the leaf is twice-pinnate if the primary divi- 

 sions are themselves pinnate (Fig. 36) ; thrice-pinnate if 

 the sulnlivision is carried through another stage ; and 

 decompound if still more divided. 



It is intprnrnptcdly -pinnate if, as in Tomato, tliere are 

 smaJl Ieafl«'t< iiirfr.;i>4'r<if<l among the larger ones (Fig. 37). 



(b) Palmati : it the leaflets are spread out from the 

 end of the petiole, like fingers (Fig. 38). 



A compound leaf is further described by mentioning 

 the numl)er and form of the leaflets. (An example of the 

 complpte description of a comi>ound leaf is given at the 

 beginning of the leaf-schedules later on). 



Venation, 



Strauwit-veixkI) : when the veins run nearly parallel, either 

 from end to end of the leaf, as in grasses (Fig. 39), or 

 from n central rib to the margin, as in Calla (Fig. 40). 



Nkt-veinei>: when the veins run in all directions, forming a 

 net-work. Such a leaf is 



(a I pinmitely-net-vrinrd : when thorn a distinct cen- 

 tral rib with the smaller veins branching from it on each 

 side fFig. 41) ; and 



(b» palmntrl i/-fwt-veinrd : when there are several chief 

 ribs radiating from the end of the petiole (Fig. 42). 



Outline. 



1. Of leaves nearly alike at both ends. 

 Filiform : thread-like, as in Asparagus. 

 AcicUi.AU : ne*'dlo-«]if»j.o.l, as in Pine (Fie. 13), 





' r\«. 41. 



Flflr. 42. 



